Autonomous vehicles and driving assistance systems are currently being developed and deployed to provide safety, reduce an amount of user input required, or even eliminate user involvement entirely. For example, some driving assistance systems, such as crash avoidance systems, may monitor driving, positions, and velocities of the vehicle and other objects while a human is driving. When the system detects that a crash or impact is imminent the crash avoidance system may intervene and apply a brake, steer the vehicle, or perform other avoidance or safety maneuvers. As another example, autonomous vehicles may drive and navigate a vehicle with little or no user input. However, due to the dangers involved in driving and the costs of vehicles, it is extremely important that autonomous vehicles and driving assistance systems operate safely and are able to accurately navigate roads, avoid objects, and observe their surroundings. Furthermore, current autonomous vehicles and driving assistance systems may struggle to operate safely or correctly due to the wide variety of terrain, weather conditions, and other environments in which vehicles often operate. Thus, autonomous vehicles must operate safely under adverse conditions and perceive the environment as accurately as possible, even if some of the vehicle's sensors fail.